I'm not sure where you asked (perhaps I missed it?), but here is a somewhat related question with some answers on intfiction.org:
http://www.intfiction.org/forum/viewtop ... =6&t=11519The basic idea (as I took it) is to build the game you want, and if you do it well, people will play it. Perhaps you're asking "what size makes a game good?" But I don't think there is a hard and fast answer for that. I would say: make the game as you would want to play it, make it so you enjoy it, and others will as well. There can't really be any other answer.